【案例+源码】详解MVC框架模式及其应用
写在开头： 首先我们需要知道，框架模式、模式、开发模式是三种不同的概念， 但他们的目的都一样：解耦！
1、关于MVC框架模型
- MVC是三个单词的缩写：
M，Model（模型）；V,View( 视图 )，C，Control（控制）。
- Model层：实现系统的业务逻辑(javaBean)
View层：负责与用户交互，即在界面上展示数据对象给用户(html，jsp)
Control层：Model与View之间沟通的桥梁，它可以分派用户的请求并选择恰当的视图以用于显示，同时它也可以解释用户的输入并将它们映射为模型层可执行的操作(Servlet)
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2、MVC设计登录案例
MVC框架模型之间的关系处理：
2.1设计登录案例交互图
2.1.1明确各个模型：
2.2项目结构图一览
2.3、代码部分
2.3.1View视图层代码
login.jsp:
<%-- Created by IntelliJ IDEA. User: 编程小哥令狐 Date: 2020/10/8 Time: 22:00 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> </head> <body> <center> <form action="UserServlet" method="post"> <h4>登录</h4> <hr/> 姓名：<input type="text" name="username"/><br/> 密码：<input type="password" name="password"/><br/> <input type="submit" value="提交"/> </form> </center> </body> </html>
success.jsp:
<%-- Created by IntelliJ IDEA. User: 编程小哥令狐 Date: 2020/10/8 Time: 22:00 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> </head> <body> <center> <h3>登陆成功</h3> <%--<a href="<%= path %>/login.jsp">后退</a>--%> </center> </body> </html>
unsuccess.jsp:
<%-- Created by IntelliJ IDEA. User: 编程小哥令狐 Date: 2020/10/8 Time: 22:00 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> </head> <body> <div style="text-align: center;"> <h3>登陆失败</h3> <%--<a href="<%= path %>/login.jsp">后退</a>--%> </div> </body> </html>
2.3.2Controller控制层代码
UserServlet.java：
package com.mvc.servlet; import com.mvc.javabean.User; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; public class UserServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { this.doPost(req, resp); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String userName = req.getParameter("username"); String password = req.getParameter("password"); User user = new User(); if(user.validatorUser(userName, password)){ resp.sendRedirect("success.jsp"); } else{ resp.sendRedirect("unsuccess.jsp"); } } }
2.3.3Model模型层代码：
User.java:
package com.mvc.javabean; public class User { public boolean validatorUser(String username, String password){ if(username.equals("admin") && password.equals("admin")){ return true; } else{ return false; } } }
2.4、Web.xml配置
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0"> <display-name>MVC</display-name> <welcome-file-list> <welcome-file>login.jsp</welcome-file> </welcome-file-list> <servlet> <servlet-name>UserServlet</servlet-name> <servlet-class>com.mvc.servlet.UserServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>UserServlet</servlet-name> <url-pattern>/UserServlet</url-pattern> </servlet-mapping> </web-app>
我们默认了账号密码为：admin，你输入的数据会和它进行比较，进而做出不同的页面跳转。
